Cecil Moore wrote:
Gene Fuller wrote:
I am impressed! That's a pretty fancy o'scope you got. Measurement of
voltages to four significant digits at t = 0 + delta-t is definitely
world-class. That 291.4 ohm line is pretty special as well.

Your non-technical diversions are noted. How about discussing
the technical question that was posed?

The voltages can be viewed on an o'scope. Their magnitudes
agree with the above calculated magnitudes. Do you know
of any reason that those voltages would not obey the
rules of the reflection model? When does a reflection
coefficient of 0.707 not reflect 0.707 of the incident
voltage?

The 291.4 ohm line is chosen to make rho=s11=0.707. My "450"
ohm ladder-line measures to be actually 380 ohms. Nothing
special about 291.4 ohms except that:

(291.4-50)/(291.4+50) = 0.707

We could actually design a feedline with Z0 = 291.4 ohms.
Want me to show you how? :-)

If you don't like that value, use 300 ohms and 51.5 ohms
for the coax. I'm sure between the choices of 50 ohm
coax and 52 ohm coax, there must be a 51.5 ohm coax in
there somewhere.


Cecil,

You rarely reply directly to anything, and this is no exception. I was
commenting on the *actual measurement* that you claimed. You added the
emphasis, not me. Perhaps it was a *virtual measurement* instead? Do you
find that you can achieve the desired results more often with such
measurements?

8-)

73,
Gene
W4SZ